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DEPARTMENT OF HEALTH AND HUMAN SERVICES

FOOD AND DRUG ADMINISTRATION

CENTER FOR FOOD SAFETY AND APPLIED NUTRITION

FOOD ADVISORY COMMITTEE MEETING

Advice on CFSAN'S Draft Report:

Approaches to Establish Thresholds for Major Food Allergens and for Gluten in Food

Thursday, July 14, 2005

8:30 A.M. to 5:20 P.M.

Greenbelt Marriott

6400 Ivy Lane

Grand Ballroom

Greenbelt, Maryland 20770

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P A R T I C I P A N T S

FOOD ADVISORY COMMITTEE STANDING MEMBERS:

Richard A. Durst, Ph.D. - Acting Chairman

Jeffrey A. Barach, Ph.D. (Industry Representative)

Patrick S. Callery, Ph.D.

Dennis Gonsalves, Ph.D., M.S.

Jean M. Halloran (Consumer Representative)

Douglas C. Heimburger, M.D., M.S.

Margaret C. McBride, M.D.

Mark Nelson, Ph.D. (Industry Representative)

Carol I. Waslien Ghazaii, Ph.D., R.D.

TEMPORARY VOTING MEMBERS:

Petr Bocek, M.D., Ph.D. (Absent 7/14/05 Session)

Margaret Briley, Ph.D., R.D.

Erica Brittain, Ph.D.

Ciaran P. Kelly, M.D.

Soheila June Maleki, Ph.D.

David O. Oryang

Marc D. Silverstein, M.D.

Suzanne Teuber, M.D.

FOOD AND DRUG ADMINISTRATION:

Robert E. Brackett, Ph.D. - Director

Food and Drug Administration, CFSAN

Catherine Copp, J.D. - Senior Policy Advisor

Food and Drug Administration, CFSAN

Steven M. Gendel, Ph.D. - Senior Scientist

Food and Drug Administration

National Center for Food Safety and Technology

Rhonda Kane, M.S., R.D. - Consumer Officer

Food and Drug Administration, CFSAN

Marcia Moore, Food Advisory Committee, Executive Secretary

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P A R T I C I P A N T S (Continued)

FOOD AND DRUG ADMINISTRATION STAFF:

Michael M. Landa, J.D. - Deputy Director for Regulatory Affairs

Food and Drug Administration, CFSAN

Stafano Luccioli, M.D. - Senior Medical Advisor

Food and Drug Administration, CFSAN

GUEST SPEAKERS:

Pekka Collin, M.D., M.P.H. - Professor

University of Tampere, Medical School, Finland

Catherine L. Copp, J.D.

Policy Advisor, CFSAN, FDA

Alessio Fasano, M.D. - Professor of Pediatrics

Medicine & Physiology and Director, the Mucosal

Biology Research Center, Center for Celiac

Research, University of Maryland School of

Medicine

Steven M. Gendel, Ph.D. - Senior Scientist

National Center for Food Safety and Technology, FDA

Rhonda R. Kane, M.S., R.D. - Consumer Safety

Officer CFSAN, FDA

Donald Kasarda, Ph.D. - Consultant and Retired

Senior Scientist, Agriculture Research Service,

USDA

Cynthia Kupper, R.D., C.D. - Executive Director

Gluten Intolerance Group of North America

Joseph A. Murray, M.D. - Professor of Medicine

The Mayo Clinic of Rochester, Minnesota

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C O N T E N T S

PAGE

Call to Order and Welcome and Introductions

Richard Durst, Ph.D., Acting Chairman 6

Use of Gluten Thresholds

Catherine L. Copp, J.D., CFSAN, FDA 9

Introduction to Celiac Disease

Joseph Murray, M.D. 11

Patient Perspectives on Celiac Disease

Cynthia Kupper, R.D., C.D. 69

Grains

Donald Kasarda, Ph.D., USDA 84

Question and Answer Session 108

Prospective Studies

Alessio Fasano, M.D. 114

Question and Answer Session 146

Retrospective Studies

Pekka Collin, M.D., M.P.H. 161

Question and Answer Session 182

International Perspectives on Gluten-Free

Rhonda S. Kane, M.S., R.D., CFSAN, FDA 186

Question and Answer Session 198

Public Comments:

Elaine Monarch 212

Alice Bast 220

Mary Schluckabeer 225

Tom P. Sullivan 232

Steve Taylor 240

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C O N T E N T S

PAGE

Overview of Approaches to Establishing

Thresholds: Gluten

Steven M. Gendel, Ph.D. 253

Question and Answer Session 257

Committee Discussion:

Panel Discussion with Guest Speakers 259

Gluten and Celiac Disease - FDA Questions 287

Revisit Food Allergens 354

Adjournment

Richard Durst, Ph.D., Acting Chairman 363

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P R O C E E D I N G S

CALL TO ORDER AND WELCOME AND INTRODUCTIONS

CHAIRMAN DURST: Good morning. I would

like to call the meeting to order. All right, I

would like to welcome everyone back and also

welcome new participants in our meeting this

morning.

For those of you who weren't here

yesterday, there is a "Conflict of Interest

Statement" over on the table, if you want to refer

to that at all, otherwise I would also ask again

that maybe our participants or our members of the

Food Advisory Committee would introduce themselves

again for the benefit of those who were not here

yesterday.

I am Dick Durst, professor [of]chemistry at

Food Science and Technology Department at Cornell

University.

Marc, would you start it off?

DR. SILVERSTEIN: Marc Silverstein, I'm a

general internist and geriatrician at Baylor Health

Care System in Dallas.

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DR. TEUBER: Suzanne Teuber, I am an

allergist at UC-Davis.

MR. ORYANG: I am David Oryang. I am a

risk analyst and agricultural engineer at the

United States Department of Agriculture, Animal and

Plant Health Inspection Service.

DR. KELLY: Good morning. Ciaran Kelly, I

am a gastroenterologist at Harvard Medical School

in Boston.

DR. MALEKI: I am Soheila Maleki. I am a

scientist with the USDA.

DR. BRITTAIN: Erica Brittain, I am a

statistician at the National Institute of Allergy

and Infectious Disease.

DR. BRILEY: Margaret Briley, University

of Texas at Austin, nutritionist.

MRS. MOORE: Marcia Moore, I am the

executive secretary for the Food Advisory Committee

and the Food and Drug Administration.

DR. WASLIEN: I am Carol Waslien,

nutritional epidemiologist at the School of

Medicine, the University of Hawaii.

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DR. BRILEY: I am Margaret McBride, child

neurologist at Akron Children's Hospital.

DR. CALLERY: Pat Callery, West Virginia

University, pharmaceutical scientist.

DR. GONSALVES: I am Dennis Gonsalves, a

scientist at USDA.

DR. HEIMBURGER: I am Doug Heimburger, a

physician and nutrition specialist at the

University of Alabama at Birmingham.

DR. BARACH: Jeff Barach with Food

Products Association here, in Washington, D.C., in

regulatory affairs.

DR. NELSON: Mark Nelson with the Grocery

Manufacturers Association here, in Washington,

D.C., and I am responsible for scientific and

regulatory policy.

MS. HALLORAN: Jean Halloran with

Consumers Union located in Yonkers, New York, and I

am director of food policy initiatives.

CHAIRMAN DURST: Thank you very much.

I would also like to remind everyone and

also for our new people here at the meeting that

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the "Charge" of the Committee is written out on the

meeting document. The most important thing is that

we are focusing on the "Threshold Working Group

Draft Report on Approaches to Establish Thresholds

for Major Food Allergens and for Gluten in Food."

We are not here to set any kind of

thresholds or discuss the labeling of these foods

for allergens, but strictly to make comments on the

best approaches to use for setting these

thresholds.

Did I cover everything that we need to?

(No verbal response.)

CHAIRMAN DURST: In that case, let's begin

with our first presentation. This is

Catherine Copp, the policy advisor for CFSAN, FDA,

on the use of gluten thresholds.

USE OF GLUTEN THRESHOLDS

MS. COPP: I have been asked this morning

to proceed with discussion on gluten and threshold

levels for gluten or possible thresholds for gluten

framework. It is similar to yesterday. I simply

want to provide you with some context for the

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evaluating the Draft Report portion that addresses

gluten in food. This is the hazard of being first.

(Slide.)

MS. COPP: Yesterday, I mentioned the Food

Allergen Labeling and Consumer Protection Act.

This is a new law that Congress passed last August.

Although it focuses primarily on allergens, food

allergens, Congress also directed FDA to address

the separate problem of gluten in food.

When I say directed, I mean that Congress

has mandated that the Agency consider and then

establish regulations according to a schedule to

define "gluten-free" for use on food labels and

also to identify the appropriate use of the term.

As with Allergens, for consumers with

celiac disease, strict avoidance of gluten at

levels that will elicit an adverse effect is the

only means to prevent potentially serious

reactions.

Accurate, complete and informative

labeling on foods can help these consumers achieve

their goal. We believe that understanding

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thresholds for gluten and having a sound scientific

framework for evaluating the existence of such

thresholds will help FDA develop a definition of

gluten-free and identify appropriate use of the

term. That's it.

Thank you.

CHAIRMAN DURST: Does anyone have any

comments or question on Catherine's presentation?

(No verbal response.)

CHAIRMAN DURST: Okay. We will move on

then to the presentation from Dr. Joseph Murray,

professor of medicine at the Mayo Clinic of

Rochester, Minnesota, on the introduction to celiac

disease.

INTRODUCTION TO CELIAC DISEASE

DR. MURRAY: Good morning, Committee

Members. I will be providing a general overview to

celiac disease.

(Slide.)

DR. MURRAY: First of all, we will discuss

what is celiac disease. We will discuss, briefly,

the pathogenesis of the disease; who gets it; what

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the treatment is, at least in a very relatively

superficial fashion. We will discuss some of the

complications and compliance issues of celiac

disease and a prognosis or future of celiac

disease.

(Slide.)

DR. MURRAY: Obviously, yesterday was

focused on food allergies. "Celiac disease" is one

of the food intolerances that is immune-mediated,

though it is not thought to be IgE-mediated; so, it

comes into the non-IgE-mediated food intolerances

that are mediated by an immune response.

(Slide.)

DR. MURRAY: Where does it happen? It

happens within the smaller intestine, predominantly

the proximal, smaller intestine is the workhorse of

the digestive system. It is this surface of the

intestinal lining that is maximally expanded by the

development of circular folds and on top of these

circular folds the so-called "villi," these villi,

shown here in a histological picture, which

maximize the digestive surface area.

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It is on the surface entrocytes of these

villi that most of the enzymes and in the layer

immediately above that in the lumen where most

digestion of the macromolecules from nutrition are

broken down and then absorbed. This is just a

picture. It looks like one of those shag-ply

carpets from the 1970s. This is a normal

appearance.

(Slide.)

DR. MURRAY: However, celiac disease is an

inflammatory state of the small intestinal mucosa.

It occurs in those who are genetically predisposed,

and it resolves, the damage resolves, with

exclusion of dietary gluten.

Here, on the left, is a normal intestine

with a normal villus structure; and on the right,

fully evolved celiac disease with complete

destruction.

The villi are gone, not only are they gone

but this entire intestinal mucosa is greatly

thickened and filled with inflammatory cells. This

is where the primary site of injury occurs in

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celiac disease.

I didn't mention it, but it is a permanent

condition. While it will heal most of the time

with exclusion of gluten, the intolerance to gluten

is permanent and will recur when the individual is

reexposed to gluten.

(Slide.)

DR. MURRAY: Now, what causes celiac

disease?

(Slide.)

DR. MURRAY: We know there are two major

components to this disease: the first is the

genetic background of predisposition.

Much of that predisposition revolves in

the HLA type, which is part of our human leucocyte

antigen-recognition system. It is how we determine

self- and non-self and generate an immune response

as appropriate and its interaction with

environmental factors, primarily the environmental

factor of gluten.

These two conspire together to produce an

immune response that becomes out of control

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resulting in inflammation, which we just showed to

you, that occurs primarily in the proximal small

intestine and then subsequently the consequences of

this inflammation leading to malabsorption and

symptoms.

(Slide.)

DR. MURRAY: What do we know about the

genetics of the disease? For many years, we know

there is a strong, familial predisposition to the

disease.

If you are unlucky enough to be a

monozygous twin of somebody affected with celiac

disease, your concordance rate is 80 percent. It

is not 100 percent, but it is about 80 percent. If

you are a sibling of a celiac, your chance of

having it is 10 percent. If you are a child of,

about 5 to 10 percent.

There is a very strong association with

certain HLA molecules. These are Class II MHC

molecules but particularly two types. First, DQ2

is the predominant type that is required for celiac

disease, and in some populations DQ2 is also an

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enabling type.

These genes, however, while they are

essentially required for the disease, are not

sufficient alone to the development of the disease.

Probably 30 to 40 percent of the Caucasian

population carry one or both of these molecules,

but most of them don't get celiac disease. There

are other HLA genes that are likely involved,

though they have not been well elucidated and

certainly not confirmed in many populations.

There are other chromosomal disorders --

Down's syndrome, Turner's syndrome, and Williams

syndrome -- that are associated with a greatly

increased risk of developing celiac disease for

reasons that are not entirely clear, but probably

are associated with the increase risk of disease in

those chromosomal disorders.

(Slide.)

DR. MURRAY: Looking at the primary

environmental trigger for the disease -- that is,

gluten -- it is basically the storage proteins that

come from these particular cultivated grasses:

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wheat, barley, rye, and other similar grains from

within those families. Other grasses -- for

example, rice, items such as corn, sorghum, millet,

and probably not even oats -- are not involved in

triggering the disease.

(Slide.)

DR. MURRAY: It is the storage proteins

from the endosperm compartment of the wheat kernel

particularly, and those are gliadins oar glutenins

that are thought to contain the antigenic moieties

that trigger the disease.

(Slide.)

DR. MURRAY: What is it about these wheat

proteins? Well, if you take wheat, as an example

of the others, these storage proteins are uniquely

high in certain amino acids, especially glutamines

and prolines.

Over 30 percent of the amino acids in

gliadin are glutamines. The glutamines, of course,

can be cross-linked to give the grain its

resiliency. Really the cooking ability, the

ability to use wheat as such an effective way of

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making things that stick together like bread, for

example, and maintain their shape, is largely a

property of these particular combinations of amino

acids.

The proline sequences that contain or

proline residues contained within the wheat

proteins also appear to form helices, and these

helices are resistant to digestion within the

mammalian gut.

(Slide.)

DR. MURRAY: This may be a key factor in

what results in the likelihood of these peptides

basically being maintained and becoming, then,

still available for the immune system to recognize

in a patient with celiac disease.

Now, gliadin molecules are presented by

these HLA types to T-cells in the intestine, and

T-cells that are specifically primed to respond to

gluten. There are certain gliadin molecules that

have a higher affinity than others for these

Class II molecules and then the T-cell receptor.

These peptides may be processed or altered

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within the gut, perhaps, to make them more

antigenic. They may not start out very antigenic,

but then they undergo some change within the gut

that may make them more antigenic.

It turns out that some of these peptides

that are particular immunodominant, these are the

ones that are most likely to produce an immune

response, that those immunodominant peptides may be

digestion resistant because they contain those

proline sequences that perform helix, making them

relatively poorly digestible by peptidases within

the gut.

(Slide.)

DR. MURRAY: Now, it turns out that there

is a contribution to this antigenic nature from

within the intestine itself, and this may well be

because of this enzyme tissue transglutaminase.

This is an enzyme that is present within

the gut mucosa. It is released by cells,

especially fibroblasts when they become inflamed,

and it cross-links cystine residues.

It turns out that it will also act on

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gliadin by deamidating some of those glutamine

residues, some specific glutamine residues, to

glutamates, making it more antigenic by deamidating

that gliadin peptide and making it fit more

perfectly or with a tighter affinity into the

binding groove of the DQ2-HLA molecule, and, hence,

producing a more vigorous immune response within

the gut.

(Slide.)

DR. MURRAY: This is a schema, a

relatively simplified schema, of what I have just

talked about. We start with wheat. You look at

particularly the ethanol-soluble fraction, and

gliadin is probably broken up into smaller

peptides, but still of a sufficient size to produce

an immune response.

It is taken up across the epithelium

presented by antigen presenting cells to the

T-cells. These are T-cells that will specifically

respond to gluten then producing two types of

responses: a cellular response, characterized by

lymphocytes producing interferon gamma and possibly

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other cytokines. It is probably the cellular

response that leads to the "inflammatory cascade"

that produces the damaged epithelium characteristic

of celiac disease.

It also produces help to the B-cell side,

to produce plasma cells that produce antibodies.

These antibodies are directed both against the

exogenous antigen gliadin and also antibodies

against tissue transglutaminase or what was known

as an the endomysial antibody. It is not known

what the actual pathogenic role of this is, but it

is a very useful serologic or blood marker for the

disease.

I mentioned about the antigen getting

changed by tissue transglutaminase. This is a

little cartoon which shows the peptide derived from

gluten. If you change one specific glutamine to a

glutamic acid, which could be done by tissue

transglutaminase, this then binds much more

tightly. This is the HLA molecule here on the

surface of the antigen presenting cell, and it fits

more perfectly into the T-cell receptor, producing

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a more potent T-cell response.

(Slide.)

DR. MURRAY: Now, there are other things

that happen in the setting of celiac disease, and I

am really touching just on the surface of many of

these, but there are other things that result in

this inflammation that damage the lining of the

intestine.

For example, there are metallic proteases

that damage the structural elements that maintain

the structure that maintain villus structure.

There is endothelial injury that occurs affecting

the blood vessels in the villus. There are

antibodies, autoantibodies, that are produced that

affect actin that are involved in the site

maintaining the structure of the entrocyte itself.

(Slide.)

DR. MURRAY: Recently, there has been work

suggesting that there is a molecule called

"zonulin" that may be released in the setting of

celiac disease.

This is important because it opens up

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tight junctions between entrocytes which may allow

even more ready access of the antigen, the foreign

antigens, between the cells into lamina propria

where antigen-presenting cells can then present

those peptides to the gluten-responsive T-cells,

further accelerating the disease.

(Slide.)

DR. MURRAY: Now, I pointed out that many

people, 30 percent or more of the Caucasian

population, carry DQ2 or DQ8. Virtually, the

entire population are exposed to gluten, but most

people don't get the disease.

There must be triggers that produce the

disease. There is evidence that suggests that

gluten in the infant diet, specifically the age of

introduction of gluten into the infant's diet, may

be important in triggering or at least producing

autoantibody markers suggestive of celiac disease

early in life.

It is not clear, however, if that changes,

whether you delay introduction or not whether that

changes, the lifetime risk of celiac disease, but

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it certainly seems to be important in triggering or

producing evidence in childhood at least of celiac

disease immune markers.

The amount of gluten in the child's diet

may be important. There are other events such as

pregnancy, infection, or surgeries that may bring

previously asymptomatic celiac disease to clinical

presentation.

(Slide.)

DR. MURRAY: One could speculate, and I

think this is based on some data, putting data

together, that one's risk for celiac disease starts

with your HLA type. Only those who carry HLA types

are at risk. You, then, are exposed to gluten.

Perhaps the timing of exposure is important,

developing in some individuals a sensitivity to

gluten.

Then, with the interaction of other

factors such as other genes other than HLA, other

things that may predispose one to autoimmunity

including gender and other events that may occur --

gastroenteritis, aging, postsurgical or postpartum

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changes in the immune system that may occur -- may

lead to a loss of tolerance, inflammation, and

subsequent malabsorption.

(Slide.

DR. MURRAY: Don Kasarda, who is here once

used the term or suggested that celiac disease was

a collision between our evolution of our immune

system and our ability to recognize self and

non-self through the HLA system and our cultivation

of wheat and these other grasses. This collision

occurs in the intestine.

(Slide.)

DR. MURRAY: Now, when this collision

occurs and results in damage, how does it present?

And who gets the disease?

(Slide.)

DR. MURRAY: Well, this is classic celiac

disease, and this is the way that I certainly

learned about celiac disease. A severe

malnourished child with evidence of malnutrition

often associated with the large, swollen abdomen

but great muscle, terrific muscle, wasting and

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protein-calorie malnutrition with symptoms that

would occur sometime after the onset of gluten

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